Evaporative control system

摘要

An evaporative control system for conventional or hybrid vehicles includes a fuel tank for storing a volatile fuel and an engine having an air induction system. A primary canister contains a first volume of a first adsorbent material, a vapor inlet coupled to the fuel tank, a purge outlet coupled to the air induction system, and a vent/air inlet. A secondary canister is coupled to the vent/air inlet and contains a second volume of a second adsorbent material that is different than the first adsorbent material. The first and second adsorbent materials adsorb fuel vapors when the engine is not running to reduce breakthrough and desorb fuel vapors when the engine is running. The second adsorbent material adsorbs butanes and pentanes at low concentrations. The second adsorbent material includes activated carbon derived from a coconut shell and a heater.